A digital television receives broadcasting contents in a moving picture experts group (MPEG) format to display an image. The MPEG format includes an intra frame (i-frame), a predict frame (p-frame), and a bidirectional frame (b-frame) since a large amount of information is compressed and provided. Among them, the i-frame to which a method of compressing a still image is applied becomes a reference frame of a continuous screen.
Therefore, since the i-frame is a key-frame of specific image data, when a viewer viewing the television changes a channel, information of the changed channel that is new channel is not displayed on the television until an i-frame for the new channel is transmitted. A time between a point in time in which the viewer inputs channel changing instructions to a point in time in which a display screen displays the contents of the new channel is called a channel changing time or a channel zapping time. Research has been attempted in order to decrease the channel changing time. However, currently, it has been known that a channel zapping time of about several seconds is required.